A fluid is sometimes injected into a hydrocarbon-formation to improve hydrocarbon production. For example, one conventional method of enhanced oil recovery (EOR) includes the injection of a fluid containing a polymer into a formation. A formation can be flooded with polymer to control (e.g., decrease) the mobility of water that is injected into the formation during a waterflood, reduce the permeability of the formation, and/or to increase sweep efficiency. The polymer can be used either alone or in combination with at least one other component, such as a surfactant. A polymer flood, as it is often called, can increase the rate and/or total volume of produced hydrocarbon and can be used as an alternative to thermal EOR methods, for example, in the production of heavy or viscous oil.
In a typical polymer flood, polymer from a source is mixed on-site with a fluid to form an injection fluid and then the injection fluid is injected into the formation through the well head equipment of one or more wells. The mixing process can vary depending on the initial state of the polymer as it is supplied. Unfortunately, it is sometimes difficult to deliver the injection fluid containing the polymer into the formation. For example, the injection fluid containing the polymer may sometimes obstruct or plug up some of the equipment, the formation, or both, which inhibits proper flow of the injection fluid into the formation. As an example, incorrect mixing of the polymer into the fluid, incomplete hydration of powder polymer, incorrect mixing ratios, or any combination of these may cause the plugging. Even fluids without polymers may sometimes cause plugging.
In short, many injection fluids sometimes cause plugging, and understanding and controlling the characteristics of injection fluids can be a significant factor in any flood to produce hydrocarbons. One such characteristic is the viscosity of the injection fluid. The viscosity can be measured before the injection fluid is injected into the formation. One method of measuring viscosity includes using an in-line viscometer that operates in real-time, for example, as described in US Patent Application Publication 2013/0298644, which is incorporated herein by reference in its entirety.
However, simply knowing the viscosity alone generally does not provide enough information about an injection fluid to avoid plugging. According to Dwarakanath et al., “Permeability reduction due to use of liquid polymers and development of remediation options,” Society of Petroleum Engineers, SPE-179657-MS, Apr. 11-13, 2016, pages 1-18, which is incorporated herein by reference in its entirety, characteristics such as long term injectivity and filter ratio may be helpful in getting a better understanding of injection fluids. However, conventional portable devices typically do not measure long term injectivity or filter ratio, and if any of these tests are performed, they typically require a laboratory setting, which leads to degradation of injection fluid samples, delays, etc.
Therefore, a need exists in the art for a better way to analyze injection fluids, especially analysis around long term injectivity and filter ratio, and especially in non-laboratory settings, such as offshore facility, remote well sites, etc.